Hello fafa,
A cluster is a datatype specific to LabVIEW, and does not exist in any other programming language. LabWindows/CVI is an ANSI C compiler, and thus, does not have a cluster datatype. Instead, you should consider using a struct, as this is essentially the same idea as a cluster.
I am not aware of any specific examples that address the problem you are working with, but there is plenty of documentation for calling DLL's that use structs. You should be able to accomplish something similar with datasocket. In fact, if you were to build a dummy VI into a LabVIEW DLL that uses the same type cluster, you'll get a header file that already has the struct defined. Check out the following resources:
Creating and Calling LabVIEW DLLs with Various Data Types from CVI
LabVIEW Data Storage
Hope this helps!